The present invention relates to an image forming unit and an image forming apparatus.
An electrophotographic image forming apparatus generally includes an image forming unit. The image forming unit is configured as an integral unit including a photosensitive drum, a charging roller, a developing roller, a supplying roller and a cleaning roller. The image forming unit further includes a detachable toner reserving container.
A toner (developer) stored in the toner reserving container is supplied to a toner hopper in the image forming unit via a toner replenishing opening. The toner supplied to the toner hopper is agitated by an agitating member, and is supplied to the developing roller by the supplying roller. The toner supplied to the developing roller is used for developing a latent image formed on the photosensitive drum (see, for example, Japanese Laid-open Patent Publication No. 2007-101718).
However, in the general image forming apparatus, the toner starts to be supplied to the toner hopper immediately after the toner reserving container is mounted to a main body of the image forming unit. Therefore, the toner may remain in the toner hopper for a long time period while being agitated. This may cause deterioration of the toner.